+(deftransform %byte-blt ((src src-start dst dst-start dst-end)
+ ((or (simple-unboxed-array (*)) system-area-pointer)
+ index
+ (or (simple-unboxed-array (*)) system-area-pointer)
+ index
+ index))
+ ;; FIXME: CMU CL had a hairier implementation of this (back when it
+ ;; was still called (%PRIMITIVE BYTE-BLT). It had the small problem
+ ;; that it didn't work for large (>16M) values of SRC-START or
+ ;; DST-START. However, it might have been more efficient. In
+ ;; particular, I don't really know how much the foreign function
+ ;; call costs us here. My guess is that if the overhead is
+ ;; acceptable for SQRT and COS, it's acceptable here, but this
+ ;; should probably be checked. -- WHN
+ '(flet ((sapify (thing)
+ (etypecase thing
+ (system-area-pointer thing)
+ ;; FIXME: The code here rather relies on the simple
+ ;; unboxed array here having byte-sized entries. That
+ ;; should be asserted explicitly, I just haven't found
+ ;; a concise way of doing it. (It would be nice to
+ ;; declare it in the DEFKNOWN too.)
+ ((simple-unboxed-array (*)) (vector-sap thing)))))
+ (declare (inline sapify))
+ (without-gcing
+ (memmove (sap+ (sapify dst) dst-start)
+ (sap+ (sapify src) src-start)
+ (- dst-end dst-start)))
+ nil))